1. Field of the Invention
This invention relates to a method of creating a unique chitosan and the use of such chitosans to form complexes with drugs to provide a drug delivery system. The present invention also relates to a method of making an implant which has enhanced efficiency of drug delivery in the specific location of an implant as a result of the use of a deacetylated, depolymerized chitosan-drug complex, as well as the related implant and the corresponding procedure for delivering the drug and implant within a patient.
2. Description of the Prior Art
As medicine has advanced in recent decades, numerous uses of synthetic prosthetic devices, including implants, have been known. One of the problems with the use of such implants is the exposure of the patient to risk of infection and other medical problems, such as pain and joint inflammation.
It is known that the physico-chemical properties, such as solubility and reactivity of chitosan, can be improved by N-deacetylation of chitin and chitosan.
U.S. Pat. No. 3,847,897 discloses the creation of a thixotropic thickener and a stabilizer made from chitin. It discloses the use of chitin for its resistance to severe food processes. The chitin may be in the form of a microcrystalline chitin in an aqueous stable thixotropic dispersion.
U.S. Pat. No. 4,286,087 discloses a method of making microcrystalline chitin powder. The molecular weight is said to be in the range of about 5,000 to 450,000.
While, in general, the use of medications which are delivered through the bloodstream has been effective for numerous conditions, the risk of infection is not adequately precluded through bloodstream delivery of drugs when there is clot formation or trauma to an affected area. As a result, there remains a need for an improved system which will effect more direct and immediate delivery of a drug in the locale where it is needed in connection with surgical implants.
There is also a need for improved drug delivery systems which involve oral administration of drugs by swallowing or positioning within the oral cavity or topical application.
There is also the problem that local delivery, in the context of implants, must be provided over a sustained period of time and, therefore, control of time release of medication is of great importance.